TITLE:
Enhancement of Photocatalytic Water Splitting Rate via Rayleigh Convection
AUTHORS:
Seiichi Deguchi, Ben Kariya, Norifumi Isu, Shoji Shimasaki, Haruna Banno, Saeko Miwa, Keisuke Sawada, Junki Tsuge, Shoichiro Imaizumi, Hidenori Kato, Kyota Tokutake
KEYWORDS:
Photocatalytic Water Splitting, Pt/TiO2 Powder, Rate Enhancement, Volumetric Reaction, Thermal Treatment, Rayleigh Convection, Thermo-Hydrodynamic Simulation
JOURNAL NAME:
Green and Sustainable Chemistry,
Vol.4 No.2,
May
16,
2014
ABSTRACT: In order to enhance photocatalytic water splitting rates with Pt/TiO2 powder, sufficient agitation of the biphasic medium is required to switch
surficial reactions to volumetric reactions. Additionally, agitation is
conducive to higher diffusion rates of the generated hydrogen and co-produced
oxygen, hindering their ability to re-couple to water on Pt loaded to TiO2 powder. In order to create agitation without consuming any electricity, a novel
technique utilizing Rayleigh convection was applied, and its ability to enhance
photocatalytic water splitting rates was evaluated. Higher Rayleigh convective
flow rates resulted in higher photocatalytic water splitting rates. Utilization
of Rayleigh convection approximately doubled the photocatalytic water splitting
rates, despite relatively low convective flow velocities (obtained through
simple thermo-hydrodynamic simulations). The rate enhancement achieved through
Rayleigh convection is a result of its ability to disperse the ultrafine Pt/TiO2 particles throughout the whole medium, leading to volumetric reactions.